Electrical heating element



R. B. DUGGAN ETAL 3,086,187

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April 16, 1963 Filed May 20, 1960 INVENTORS @ose-97' BEA/wmv DueGm BY/wuar flu-,96o ffm/weke' :Uma ATTORNEY April 16, 1963 R. B. DUGGAN ETAL ELECTRICAL HEATING ELEMENT 2 Sheets-Sheet 2 Filed May 20, 1960 UN m ON m INVENTORS @asser BfA/14N DaGGA/Y vousr 14u-@en Kwai/fk5 BYA @uw K. M

uw; ATTORNEY United States Patent ce 3,085,187 Patented Apr. 16, 1963 j 3,086,187 ELECTRICAL HEATING ELEMENT Robert Beaman Duggan and August Alfred Klapheke,

Louisville, Ky., assignors to American Radiator 8:

Standard Sanitary Corporation, New York, NX., a

corporation of Delaware Filed May 20, 1960, Ser. No. 30,677 l 2 Claims. (Cl. 338-283) The present invention relates to an electrical heating element and more particularly to an improved electrical heating element which utilizes convective and also rad1ant heat transfer and which is adapted to be applied to a baseboard installation.

The present invention is an improvement on pending United States patent application S.N. 20,671, filed Apr1l 7,1960, now Patent No. 3,041,569, of Herwart Werker for Improvements in a Heating Element.

The heating element described and shown in the Werker application discloses an electrical heating element 1n which a sheet, preferably an elongated strip, of electrical resistance is provided with two conductors, one along or adjacent each of the longitudinal edges of the material. In this manner, since the conductors are electrically bonded to the material, current ows from one conductor to the other through the electrical resistance material to produce heat. The amount of heat is substantially directly proportional to the length of the heating element, ie., its dimension longitudinally of the conductors. If the heating element is lengthened, the effective resistance will decreasesince, in eiect, increments of resistances in parallel are being added, which will increase the current thereby increasing the heat output.

The present invention has for one of its objects the provision of an improved heating element which has novel means of mounting the conductors on the strip of electrical resistance material.

Another object of the present invention is the provision of an improved heating element which will eliminate any sparking by vproviding a good electrical bond between the conductors and the strip of resistance material.

Another object of the present invention is the provision of an improved heating element which is folded in such a manner as to give maximum heat per unit space.

Another object of the present invention is an improved heating element adapted to be mounted in a baseboard installation.

Other and further objects of the present invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein Will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. l is a side elevational view showing an electrical heating element made in accordance with the present invention;

FIG. 2 is a sectional view taken along line 2-2 of FIG. l showing the means for mounting the conductors on the strip of resistance material;

FIG. 3 is a modification showing another means for mounting the conductors on the strip of resistance material;

FIG. 4 shows another modification of the means for mounting the conductors on the strip of resistance material;

FIG. 5 is a plan View showing the electrical heating element of the present invention folded in order to heat more air;

FIG. 6 is a side elevational view of the folded heating element shown in FIG. 5

FIG. 7 is a top plan view showing the heating element folded in accordance with the present invention to obtain maximum heating per unit space;

FIG. 8 is a side elevational view thereof;

FIG. 9 is a perspective view showing the heating element mounted on a baseboard installation; and

FIG. 10 is a sectional view thereof taken along line 10-10 of FIG. 9.

Referring to the drawings, and more particularly to FIG. l, the heating element A comprises an elongated strip or sheet of resistance material 1 having a pair of elongated conductors 2 and 3 electrically bonded to the sheet material, one along each of its opposite edges. The current flows from one conductor to the other through the resistance material to raise the temperature of the resistance material 1. Since an increase in the length of the strip is, in eifect, the addition of increments of resistances in parallel, the over-all resistance is decreased thereby increasing the current and the amount of heat produced is in general directly proportional to the length of the heating element A.

As shown in FIG. 2 the conductors 2 and 3 are preferably U-shaped in transverse cross-sectional configuration and comprise a pair of legs 4 adapted to be clamped onto the opposite sides of the strip 1 of resistance material and a base 5 adapted to straddle the edge of the strip 1. With this arrangement it will be seen that the conductors Z and 3 may be tightly secured to the edges of the strip 1 to effect an electrical bond and so as to minimize the possibility of the conductors 2 and 3 from becoming loosened during handling.

In order to provide a good electrical bond and to securely anchor the conductors 2 and 3 on the strip 1, suitable conductive filler and bonding material 6 is interposed between the strip 1 and the conductors 2 and 3, as shown in FIGS. 3 and 4.

Referring to FIG. 3, the conductive ller and bonding material 6 is interposed between both legs 4 of the conductors 2 and 3 and the base 5 thereof. In this manner the conductive filler material 6 will fill in any spaces between the conductors 2 and 3 and the strip 1 such as might be caused by slight uneven places, thereby to provide a good electrical bond therebetween and to securely anchor the condutcors 2 and 3 in place.

FIG. 4 shows another embodiment wherein the conductive filler and bonding material 6 is disposed along one leg only of the conductors 2 and 3 and along the base 5.

The conductors 2 and 3 and the strip 1 may be coated With an insulation material 7 to prevent sparking, to eliminate shock hazards, and to prevent shorting between the bends, if they touch, as might occur in FIG. 7.

In order to increase the heat produced per unit space, the heating element A may be folded as shown in FIGS. 5 and 6 into a corrugated form having a number of oppositely directed loops 10 and 11. This creates a plurality of air channels 12 and 13 between adjacent loops 10 and 11 respectively, so as to permit a greater amount of air to be heated per unit space.

In order to obtain heating `of a maximum amount of air per unit space, the heating element is folded into oppositely directed loops 14 and 15, in the manner shown in FIGS. 7 and 8, so that the loops 14 are squeezed together into sidewise adjacency or contact with each other and oppositely directed loops 15 are also squeezed together into side-wise adjacency or contact -with each other. The insulation 7 will prevent any shorts between the loops in contact with each other. With this arrangement it will be readily seen that a maximum length of the heating element A can be squeezed into a minimum amount of space thereby permitting maximum heating per unit space. It will be understood, of course, that the deeper the loops 14 and 15 are the more air will be heated since a greater length of the heating element A is used.

The heating element A may be used in a baseboard installation B as shown at FIGS. 9 and 10. The baseboard B comprises a back panel 30 which is adapted to be mounted to the Wall of a room at oor level by means of screws 31 or other suitable means. The back panel 30 is adapted to have a plurality of holding brackets 32 of which only one is shown) hung thereon by means of the tongues 34 which fit in the pockets 33 formed from or by the bent out portions on the back panel 30. The slot or aperture 16 tits over the pocket 33 allowing the tongue 34 on the bracket 32 to be inserted into pocket 33. The pockets 17 similar to pockets 33 at the lower portion of back panel 30 receive the bottom end 35 of the brackets 32 and aid in holding the brackets 32 in place.

Each of the brackets 32 has an upwardly extending cover-supporting element 18 to which the cover 19 is attached and is also provided with a support base 20 adapted to receive the heating element A, which may be attached thereto by any suitable means. The cover 19 is hung on the cover-supporting elements 18 and is held in place by a downwardly extending lip 21 on each of the bases 20. Suitable caps or covers 22 are slipped on or clamped to the ends of the housing to nish the baseboard.

With this structure the heating element A is installed on the support bases 20 and the cover 19 is mounted on the brackets 18. When current flows through the heating element A in the manner described above, the heat produced will be dissipated by convection throughout the room from the space between cover 19 and over-hanging portion 23 of the back panel 30, the air which was heated and dissipated throughout the room being replenished through the space below cover 19 through the open underside of the baseboard and also through opening 24 in base 20, as shown by the arrows in FIGS. 9 and 10. A portion of the heat produced in the manner described above will be dissipated throughout the room by radiation from the cover 19.

It will be seen that the present invention provides an improved heating element which has novel means for mounting the conductors onto the resistance material which provides a good electrical bond between the resistance and the conductor. The present invention also provides a heating element which will give maximum heating per unit space and which may be easily mounted in a baseboard installation.

Due to the simplicity of construction of the bascboard heating elements as disclosed, they may be readily cut with a tin snip lor added to by joining elements end to end to provide the desired amount of radiation needed in a room.

It will be apparent that the design of my electrical baseboard elements is such that they can be easily installed thereby making the installation of this form of heating just as economical as conventional forced circulation baseboard radiators.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. In an air heating device, a strip of electric resistance sheet material, a pair of U-shaped electric conductors straddling the longitudinal edges of the sheet material and extending lengthwise of said material and in electric conducting Contact therewith throughout the length of said material, said material being so constituted that it may be readily and easily severed transverse to the length of said conductors and in accordance with desired heat output, said material and conductors being folded transverse to the length thereof to form opposed loops, said opposed loops being in contact with each other, means insulating adjacent loops from each other `and said material being positioned with its surface planes in the planes of air ow thereover so that the heat transfer from the resistance material to the surrounding air is multiplied for the length of the device transverse to the loops.

2. An electrical heating element as claimed in claim l, wherein conductive filler material is interposed between said strip and at least a portion of said conductors.

References Cited in the le of this patent UNITED STATES PATENTS 760,076 Leonard May 17, 1904 1,521,241 Hale Dec. 30, 1924 1,900,318 Valkenburg et al Mar. 7, 1933 2,021,486 McDonell Nov. 19, 1935 2,496,346 Haayman et al Feb. 7, 1950 2,651,504 Gundrurn et al. Sept. 8, 1953 2,902,662 Wittlake Sept. 1, 1959 3,041,569 Werker June 26, 1962 FOREIGN PATENTS 939,761 Germany Mar. l, 1956 

1. IN AN AIR HEATING DEVICE, A STRIP OF ELECTRIC RESISTANCE SHEET MATERIAL, A PAIR OF U-SHAPED ELECTRIC CONDUCTORS STRADDLING THE LONGITUDINAL EDGES OF THE SHEET MATERIAL AND EXTENDING LENGTHWISE OF SAID MATERIAL AND IN ELECTRIC CONDUCTING CONTACT THEREWITH THROUGHOUT THE LENGTH OF SAID MATERIAL, SAID MATERIAL BEING SO CONSTITUTED THAT IT MAY BE READILY AND EASILY SEVERED TRANSVERSE TO THE LENGTH OF SAID CONDUCTORS AND IN ACCORDANCE WITH DESIRED HEAT OUTPUT, SAID MATERIAL AND CONDUCTORS BEING FOLDED TRANSVERSE TO THE LENGTH THEREOF TO FORM OPPOSED LOOPS, SAID 